With 1 billion people chronically hungry and Earth's population expected to increase by 50% before the end of the century, it's time to get serious about family planning.

At one point, the prevailing wisdom was that nations needed robust birthrates to protect their economic welfare, and that if only we could produce food more efficiently, feeding the Earth's burgeoning population wouldn't be a problem. Now, with 1 billion of the world's people chronically hungry and the population expected to increase by 50% before the end of the century, we know better. Or we ought to.

A recent five-part series by Times reporter Kenneth R. Weiss detailed the multipronged dilemma facing the thinkers and global leaders whose aim is to reduce famine and sickness without devastating the world's finite resources. There would have been even higher rates of starvation already had it not been for the development of modern agricultural techniques, but the world's capacity for producing yet more food is limited. The easily arable land has been taken, and it is actually shrinking because of the encroachment of cities and suburbs; water clean enough for agriculture is increasingly tapped out in some key regions. Climate change is expected to put further strains on food production.

No one has a good solution. That's why family planning assistance is one of the most important forms of humanitarian aid that the United States and other developed nations can provide.

As a matter of policy, that can be tricky. If the U.S. makes contraception available, will it be seen as pressuring developing nations not to bring more of their numbers into the world? Some nonprofits have backed away from funding birth control after antiabortion forces pushed against it, especially during theGeorge W. Bush administration. It hasn't helped that a couple of attempts at population control have led to unpardonable coercion — forced abortions in China and forced vasectomies in India.

How big one's family should be is a highly personal choice that should not be subject to any form of coercion. As it happens, though, many women would choose to have fewer children. According to the Worldwatch Institute, 1 in 5 births results from an unwanted pregnancy. If just those pregnancies were prevented, the birthrate would fall below replacement level.

What keeps women from keeping their families smaller? Most often, poverty; they can't afford contraception. As Weiss' series showed, in many places where free or low-cost birth control is made available, demand far outstrips supply. But political, religious and cultural forces also play a part. In the Philippines, Weiss wrote, pressure from the Roman Catholic Church led to the virtual elimination of birth-control services at public clinics. In some countries, women have so few rights that they are not allowed to decide how many children they will have.

Nations also tend to view population growth within their borders as a force for their own economic well-being; ever-larger numbers of younger people mean enough workers to build up businesses and help support retirees. This view is shortsighted, however; dramatic drops in birthrates have created temporary hardships in some countries but also long-term benefits once that smaller population reaches retirement. Without the necessary resources and an existing economy prepared to absorb large numbers of new workers, nations that promote high birthrates set themselves up for economic distress and political unrest.

Even if it went only to nations that want it, increased family planning aid would make an enormous difference. Yet U.S. funding for such aid has been flat-lined for two decades, and the difference has not been made up by others.

That has to change; such assistance is one of the best ways to reduce and prevent a global litany of suffering. Of almost equal value is aid for girls' education in nations where families cannot afford it; repeated studies have found that girls who receive even a minimal amount of basic schooling choose to have smaller families.

Because of the political sensitivities around birth control, abortion and family choice, too few world leaders have been willing to openly address what is clearly one of the most important factors affecting hunger, international economics, agriculture, energy and the environment. It's a topic we have minimized at our peril.